Add an expression-tree based version of RaiseAndSetIfChanged

ReactiveXaml.Tests/ReactiveCollectionTest.cs

@@ -1,5 +1,4 @@
-using Antireptilia;
-using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
 using System;
 using System.Linq;
 using System.Collections.Generic;
@@ -8,7 +7,7 @@ using System.IO;
 using System.Text;
 using ReactiveXaml.Tests;
 
-namespace Antireptilia.Tests
+namespace ReactiveXaml.Tests
 {
     [TestClass()]
     public class ReactiveCollectionTest : IEnableLogger
@@ -165,4 +164,4 @@ namespace Antireptilia.Tests
             return obj;
         }
     }
-}
+}

ReactiveXaml.Tests/ReactiveObjectTest.cs

@@ -3,7 +3,6 @@ using Microsoft.VisualStudio.TestTools.UnitTesting;
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using Antireptilia.Tests;
 
 namespace ReactiveXaml.Tests
 {
@@ -97,10 +96,25 @@ namespace ReactiveXaml.Tests
             this.Log().Debug(json);
 
             // Should look something like:
-            // {"IsNotNullString":"Foo","IsOnlyOneWord":"Baz"}
-            Assert.IsTrue(json.Count(x => x == ',') == 1);
-            Assert.IsTrue(json.Count(x => x == ':') == 2);
-            Assert.IsTrue(json.Count(x => x == '"') == 8);
+            // {"IsNotNullString":"Foo","IsOnlyOneWord":"Baz", "UserExprRaiseSet":null}
+            Assert.IsTrue(json.Count(x => x == ',') == 2);
+            Assert.IsTrue(json.Count(x => x == ':') == 3);
+            Assert.IsTrue(json.Count(x => x == '"') == 10);
+        }
+
+        [TestMethod()]
+        public void RaiseAndSetUsingExpression()
+        {
+            var fixture = new ValidatedTestFixture() { IsNotNullString = "Foo", IsOnlyOneWord = "Baz" };
+            var output = new List<string>();
+            fixture.Subscribe(x => output.Add(x.PropertyName));
+
+            fixture.UsesExprRaiseSet = "Foo";
+            fixture.UsesExprRaiseSet = "Foo";   // This one shouldn't raise a change notification
+
+            Assert.AreEqual("Foo", fixture.UsesExprRaiseSet);
+            Assert.AreEqual(1, output.Count);
+            Assert.AreEqual("UsesExprRaiseSet", output[0]);
         }
     }
 }

ReactiveXaml.Tests/ReactiveValidatedObjectTest.cs

@@ -23,6 +23,12 @@ namespace ReactiveXaml.Tests
             get { return _IsOnlyOneWord; }
             set { RaiseAndSetIfChanged(_IsOnlyOneWord, value, x => _IsOnlyOneWord = x, "IsOnlyOneWord"); }
         }
+
+        string _UsesExprRaiseSet;
+        public string UsesExprRaiseSet {
+            get { return _UsesExprRaiseSet; }
+            set { _UsesExprRaiseSet = this.RaiseAndSetIfChanged(x => x.UsesExprRaiseSet, value); }
+        }
     }
 
     [TestClass()]

ReactiveXaml/ReactiveObject.cs

@@ -7,6 +7,7 @@ using System.Diagnostics;
 using System.ComponentModel;
 using System.Reflection;
 using System.Runtime.Serialization;
+using System.Linq.Expressions;
 
 namespace ReactiveXaml
 {
@@ -36,6 +37,7 @@ namespace ReactiveXaml
 #endif
         }
 
+        [Obsolete("Use the RaiseAndSetIfChanged<TObj,TRet> extension method instead")]
         protected T RaiseAndSetIfChanged<T>(T oldValue, T newValue, Action<T> setter, string propertyName)
         {
             // if oldValue == newValue...
@@ -56,7 +58,7 @@ namespace ReactiveXaml
               .Subscribe(_ => RaisePropertyChanged(propertyName));
         }
 
-        protected void RaisePropertyChanged(string propertyName)
+        protected internal void RaisePropertyChanged(string propertyName)
         {
             this.VerifyPropertyName(propertyName);
 
@@ -137,4 +139,37 @@ namespace ReactiveXaml
             }
         }
     } 
+
+    public static class ReactiveObjectExpressionMixin
+    {
+        public static TRet RaiseAndSetIfChanged<TObj, TRet>(this TObj This, Expression<Func<TObj, TRet>> Property, TRet Value)
+            where TObj : ReactiveObject
+        {
+            string prop_name = null;
+            FieldInfo field;
+            try { 
+                var prop_expr = ((LambdaExpression)Property).Body as MemberExpression;
+                prop_name = prop_expr.Member.Name;
+            } catch (NullReferenceException) {
+                throw new ArgumentException("Property expression must be of the form 'x => x.SomeProperty'");
+            }
+            
+            field = (typeof(TObj)).GetField("_" + prop_name, BindingFlags.NonPublic | BindingFlags.Instance);
+            if (field == null) {
+                throw new ArgumentException("You must declare a backing field for this property named _" + prop_name);
+            }
+
+            var field_val = field.GetValue(This);
+
+            if (EqualityComparer<TRet>.Default.Equals((TRet)field_val, (TRet)Value))
+                return Value;
+
+            field.SetValue(This, Value);
+            This.RaisePropertyChanged(prop_name);
+
+            return Value;
+        }
+    }
 }
+
+// vim: tw=120 ts=4 sw=4 et enc=utf8 :